The purpose of this investigator-initiated study was to evaluate the ability of Misoprotol to prevent oral mucositis and the safety and tolerability of 200 ug given orally every 8 hours compared to placebo in patients receiving preparative conditioning regimens for autologous stem cell transplant of either marrow or peripheral blood origin. A total of 48 patients participated in the study and the results have been analyzed. Several trends have been noted: a. Misoprostol as prescribed was found to be safe in hematopoietic cell transplant patients. There were no serious adverse events attributable to the drug. b. There was an approximate 40% reduction in oral mucosal injury as measured by the average Oral Mucositis Index score in active drug versus placebo recipients between BMT days +6 and +9. Oral mucosal injury was reduced by approximately 50% in the "evaluable" cohort alone, approximately one week post transplant. c. There were no clear trends toward pain reduction in the active drug recipients. d. Global quality of life measures were more variable between placebo and active drug groups. Currently, the study is suspended pending review of the interim report.